Due to the advance of communication technologies and content industries, recently, large-scale data is increasingly required to be transmitted at a high speed over a wireless channel. To transmit data at a high speed, a high transmission output and a wide transmission bandwidth are required compared to general data transmission. To perform high-speed communication, a method is required for reducing an interference signal and efficiently transferring a desired signal. As such a method, there is a smart antenna technology, namely, beamforming. Herein, beamforming as a type of smart antenna is technology that restricts transmitting or receiving antenna beam only to a target terminal as if spotlight is directed only to an actor on a stage.
To realize such a beamforming technology, a base station is required to determine a weight factor matrix for each transmitting antenna. As an algorithm for determining the weight factor matrix, a zero forcing algorithm has been proposed. The zero forcing algorithm is an algorithm which determines a weight factor matrix such that a transmitted signal toward a terminal other than a target terminal becomes zero, and thus decreases an inter-cell interference signal and a noise component.
However, the zero forcing algorithm is applied only when the number of antennas of a base station is greater than the number of antennas of all terminals, but since there are a plurality of terminals using the same channel at a multi-cell environment, the zero forcing algorithm is not useful at an actual communication environment. Therefore, a weight factor matrix determining algorithm that is capable of application irrespective of the number of transmitting and receiving antennas is required.